You can click on the black-yellowish icon in systray, on the dialog window that appears, select to trouble shoot it.
* You think systemctl is allowed to access XY.
* For each field on the right hand side you
* Copy paste the (usualy) last 2 lines (without the starting #) into a terminal, where you had loged into su. (the # indicates that the command requires root access (su/sudo))
* wait for the command to have finished
* Continue with the next lower field (last 2 lines)
This procedure may happen mostly after you have installed something new, that requires deep system access.
This may be, but not limited to:
* webserver
* mysql (or other databases)
* systemctl (part of get your system booting)
* ssh or other simliar internet tools
However, dont just allow everything showing up, but these are the most cases it should occour.
Better ask again, than allow malware to get system access
Hope this helps